Attempts have been made to modify butter in an attempt to fractionate the triglycerides, in order to produce a more spreadable butter, and/or to remove the cholesterol present in the butter. However, none of these prior art techniques has proved to be satisfactory, as they have either not satisfactorily removed the cholesterol, or in removing the cholesterol have modified the flavouring of the butter or otherwise degraded the butter by altering its physical properties, as well as its keeping properties.
Concern is being increasingly expressed at the level of cholesterol in foodstuffs. In addition to concern over the presence of saturated fats in our diet, it is likely that legislation will be enacted in some countries which will require cholesterol content to be shown along with other nutritional values when the foodstuff is sold.
The primary source of cholesterol in foodstuffs is lipid-containing food such as meat, either red or white, shell-fish, and dairy products such as butter or cheese.
The lipid components of interest are those known as neutral lipids. This class of lipids contains: mono-, di- and tri-acylglycerides, collectively known as fat; free and esterified cholesterol, and other sterols; free fatty acids, fatty alcohols and wax esters. Of most interest are the fat and cholesterol components, and in the case of butter, it is desirable to remove cholesterol from the butter without in any way degrading the fat component.